The aims of this project are: (1) to replicate and extend the results we found using a tricyclic antidepressant combined with psychophysiological therapy in the treatment of myofascial pain dysfunction (MPD) syndrome; (2) to evaluate the potential use of a tricyclic antidepressant as a therapeutic intervention for bruxism and to attempt to understand how this medication may effectively aid in the treatment of myofascial pain disorders; (3) to evaluate tonic, resting electromyographic values and mandibular posture in patients who receive splints or who receive psychophysiological therapy in order to better understand the potential etiological components of this disorder; and (4) continue our long-term follow-ups of patients treated during our previous grant periods in order to evaluate the natural course of treatment effects for both successfully treated patients. Three major studies will be completed during he proposed gant period. In the first study, we will attempt to extend the results we found using a tricyclic antidepressant with depressed patients to nondepressed patients to improve the rapidity and effectiveness of psychophysiological therapy for MPD. The second study will attempt to evaluate the effectiveness and minimal dose necessary of a tricyclic antidepressant for the treatment of nocturnal bruxism and the potential relationship of this treatment for the noted improvement in therapy of MPD patients. The third study will evaluate tonic, resting electromyographic values and mandibular posture in MPD patients and compare these two values to an appropriately matched control group. In addition, changes associated with splint therapy and psychophysiological therapy will be evaluated. This is in order to gain a better understanding of the potential etiological factors as well as the relationship of these therapies to successful outcome. It is obvious that the information gained in studying MPD can be generalized to other myofascial problems where behavioral techniques are to be used as well as the potential etiological factors associated with these disorders.